Water-Clear Low Density 10:1 Silicone Potting Compound RTV-2 Silicone Encapsulant for Optical Sensor Photodiode Encapsulation

Water-Clear Low Density RTV-2 Silicone Potting Compound HN-8808A/B for Optical Sensor, Photodiode and LED Encapsulation

HN-8808A/B is a two-component condensation-cure (tin-catalysed) RTV-2 silicone potting compound mixed at 10:1 by weight from a 2200-2600 mPa·s base and a 20-30 mPa·s curing agent. It cures at room temperature into a water-clear elastomer of 0.94 ± 0.02 g/cm³ low density, so potted photodiodes, optical sensors, LED emitters and solder joints stay visible for 100% optical and visual inspection. The cured material provides ≥ 14 kV/mm dielectric strength, a dielectric constant of ≤ 3.0, elongation at break up to 100%, waterproof and moisture-proof protection and a −50 C to 200 C service range, with good adhesion to aluminium substrates without primer and no corrosion of sealed parts.

Key Features

• Water-clear cure for optical and visual inspection - the transparent elastomer allows brightness, light output and solder joint inspection through the potting, so defects are found without destructive teardown.
• Low density 0.94 ± 0.02 g/cm³ - the unfilled low-density formula stays suspended in tall cavities, so no heavy filler settles and depth protection stays uniform around tall capacitors and connectors.
• Dielectric constant ≤ 3.0 - low Dk keeps signal delay and loss low for optical sensor drivers, high-speed digital boards and RF modules.
• Dielectric strength ≥ 14 kV/mm - electrical insulation for sensor boards, LED drivers and waterproof power supplies.
• Elongation at break up to 100% - the elastic transparent skin absorbs thermal movement and vibration without cracking or delamination from the housing.
• Primer-free adhesion to aluminium - bonds directly to aluminium substrates and heat sinks, with no corrosion of sealed metal parts.
• Small chemical shrinkage, no exotherm - condensation cure proceeds without heat build-up, so temperature-sensitive optical dies and lenses are not stressed.
• −50 C to 200 C service range - stable clarity and elasticity from cold outdoor installation to lamp and power supply heat loads.
• 10:1 mix ratio, room temperature cure - 8-24 h full cure at 25 C with optional post-cure heating at or below 60 C after initial set; 22 kg or 11 kg sets for workshop and pilot batches.

Mixing and Application

1. Pre-mix - stir Component A so any settled filler is redispersed, and stir Component B (curing agent) until homogeneous.
2. Weigh - weigh A and B at exactly 10:1 by mass on a precision scale; keep A and B stored separately in a clean, dry area.
3. Mix - mix until the colour is uniform and scrape the walls and bottom. Do not prepare very large batches by hand, because fluidity drops as curing starts; cure is faster in summer and slower in winter.
4. Degas - vacuum degas to remove entrapped air before potting.
5. Pot - pour into the clean, dry device and ensure complete coverage; protect the device surface and mixing container.
6. Cure - allow room-temperature initial cure, then full cure in 8-24 h at 25 C. Optional post-cure heating must not exceed 60 C and may only be applied after initial cure.

Critical handling notes: the freshly mixed 10:1 compound must not be heated to accelerate cure - gentle heating at or below 60 C is allowed only after initial set. Do not fully seal the potted device or heat above 100 C before the curing mass has released its small molecules; if complete sealing is required, seal after 3 days in summer or 7 days in winter, and keep the work area ventilated.

Application Coverage

HN-8808A/B is specified for transparent, waterproof and insulating encapsulation in the following assemblies:

Optical and sensing devices

• Optical sensor and photodiode - photodiode, phototransistor, photoelectric sensor, proximity optical sensor, LED chip and light guide encapsulation where light must pass through the potting.
• Display and indicator - display module edge sealing, indicator lamp, backlight unit and touch panel frame protection with visible joints.
• Camera and lens modules - lens holder sealing and image sensor board protection with inspection access.

Lighting and power supplies

• LED driver and light source - LED driver, LED power supply, lamp, light source, luminaire and lighting accessory encapsulation with brightness verification after potting.
• Waterproof power supply - waterproof power supply, adapter, charger board and outdoor power module.
• Appliance electronics - household appliance control board, electrical appliance module and small power board.

Automotive and transport electronics

• Automotive electronic module - automotive electronic module, lamp control board, sensor module and body control board.
• Aluminium substrate assemblies - aluminium substrate, aluminium heat sink and metal-core PCB potting that needs primer-free adhesion.

General electronic encapsulation

• PCB and circuit board - PCBA, connector, terminal block and relay encapsulation where inspection access is required.
• Sensor and controller - temperature and humidity sensor board, controller board and instrument module.
• Medical and laboratory devices - transparent encapsulation of diagnostic instrument boards and sensor windows.

Technical Data (TDS HANAST-TDS-027 Rev.1)

Before Mixing (Uncured Components)

After Mixing (A + B)

Cured Properties

Values are measured at 25 C and 50-60% RH after the recommended cure schedule and are for reference only; actual performance may vary with application conditions.

Packaging, Bulk Supply and Storage

• Standard kits - 22 kg per set (Component A 20 kg + Component B 2 kg) or 11 kg per set (Component A 10 kg + Component B 1 kg).
• Containers - Component A in 20 kg or 10 kg iron or plastic drums, Component B in 2 kg or 1 kg plastic bottles.
• Documentation - TDS, MSDS and RoHS declaration issued with every shipment.
• Storage - below 25 C in original tightly sealed containers, protected from sunlight, moisture and heat; reseal immediately after opening to avoid moisture contamination.
• Shelf life - 6 months unopened and properly sealed, best used within 3 months.
• Transport classification - non-dangerous goods (general chemicals); handle with care to prevent leakage and keep away from rain and direct exposure.
• Supply capacity - 50 tons per month with OEM and private label service.

FAQ

About Hanast

Shenzhen Hanast New Materials Co., Ltd. manufactures liquid silicone materials for electronic potting, thermal management and mould making, supplying OEM and private label programmes worldwide. Every lot ships with TDS and MSDS documentation and is RoHS compliant.